Pressurized dispencer with controlled release of stored reserve propellant

ABSTRACT

A gas storage and delivery system for restoring pressure as it is depleted from a pressurized container stores a reserve supply of propellant gas on a gas-adsorbing material. The propellant gas is released into the container in response to a decrease in pressure in the container to maintain a desired pressure as product is depleted. The gas-adsorbing material is wetted with a non-polar release-promoting agent to promote release of the sorbed gas in response to decreases in pressure in the container and to ensure that substantially all of the sorbed gas is obtained if needed in response to decrease in pressure in the container.

This application claims the benefit of U.S. provisional patent application Ser. No. 61/214,215, filed Apr. 21, 2009.

TECHNICAL FIELD

This invention relates to containers that dispense product under pressure. More particularly, the invention relates to pressurized dispensers that use a propellant gas to exert pressure on or with the product to dispense it through a valve when the valve is opened, and specifically to a container that stores a reserve supply of gaseous propellant adsorbed on a gas adsorbing material in the container and releases the stored gaseous propellant into the container to maintain a desired pressure level in the container as product is depleted.

BACKGROUND ART

Many products are packaged in so-called pressure pack dispensers that hold under pressure a propellant and a product to be dispensed. Propellants normally comprise either a liquefied gas dissolved in the product, or a compressed gas injected into the container to exert pressure on the product.

The amount of liquefied gas or compressed gas and the pressure at which they are pumped into the container are calculated to achieve a desired starting and ending pressure in the container. In those containers using a liquefied gas as the propellant, as product is depleted the pressure in the container drops and some of the liquefied gas gasifies to restore the equilibrium pressure. This action will continue as long as there is sufficient liquefied gas in the container to gasify and restore the pressure to a desired pressure, for example the starting equilibrium pressure. In those containers using a compressed gas as the propellant, as product is depleted the compressed gas expands to fill the space vacated by the dispensed product. As the compressed gas expands, the pressure exerted by it decreases according to Boyle's law, which states that pressure is inversely proportional to volume. Since there is nothing to restore or replenish the pressure of the expanded compressed gas, the pressure in the container falls dramatically as product is used up. To ensure that adequate pressure will remain when the container is being utilized or nearly empty of product it is generally necessary to start with a pressure that is higher than required to achieve desired discharge characteristics. Accordingly, for performance reasons liquefied gas propellants are generally preferred over compressed gas, even though compressed gases are generally environmentally friendly while liquefied gases are not.

At one time Freon®, a fluorinated hydrocarbon, was the most common aerosol propellant, but its use has been banned because it is believed to contribute to destruction of the ozone layer. Similarly, the use of chlorofluorocarbons (CFCs) has been banned because of their harm to the environment. Since the ban of these substances the majority of aerosol propellants have been based on light hydrocarbons or hydrofluorocarbons. However, these volatile organic compounds (VOCs) form atmospheric contaminants and are also now the subject of legislation and increasing pressure from the environmental lobby.

Compressed gases such as carbon dioxide, nitrogen, and air are ideal in concept for use as an aerosol propellant because of their limited impact on the environment, but the reduction in operating pressure over the life of the dispenser poses a serious drawback to their use. Carbon dioxide (CO₂), for example, is a desirable propellant because it is plentiful and non-flammable. However, its use has been limited in aerosol products because the solubility of CO₂ in the product media is low, whereby sufficient CO₂ cannot be placed in the container to maintain a desirable pressure throughout the useful life of the dispenser.

In conventional aerosol dispensers utilizing compressed gases as the propellant, a compressed gas is placed in the container in an amount and at a pressure calculated to achieve satisfactory discharge of the product throughout the useful life of the dispenser, i.e. until all or substantially all product has been discharged. Since the pressure will drop off as the product is depleted, and only a finite amount of propellant is initially placed in the container, the pressure varies considerably over the useful life of the container. As a result, the characteristics of the discharge spray may vary considerably over the useful life of the container. Also, product volume is limited to 60-65% of the container volume in order to have enough propellant gas in the container to provide enough pressure to perform during dispensing of the last 25% of product

Efforts have been made in the prior art to solve the foregoing problems and enable use of environmentally friendly compressed gases. In one such prior system a quantity of gas-adsorbing material such as, e.g., activated carbon or zeolite on which is adsorbed a reserve supply of propellant gas such as, e.g., carbon dioxide, is placed in the container, or in communication with it. In these systems gas will be released or desorbed from the sorbent material to restore or replace the expanded compressed gas and maintain pressure in the container at a desired level as product is depleted. It is intended that as product is depleted from the container and the pressure of the propellant consequently drops as it expands into the space vacated by the product, some of the propellant adsorbed on the gas-adsorbing material will be released into the container to maintain the pressure at a desired level. In practice, however, this result is not uniformly and satisfactorily achieved due to the fact that although activated carbon or zeolite is capable of adsorbing and storing a large amount of gaseous carbon dioxide, the gas is not totally desorbed. Consequently, in these prior systems only a small amount of the adsorbed gas is desorbed, specifically only about 42%, and made available to maintain the pressure in the container at a desired level throughout the useful life of the container.

Applicant sought to overcome this problem in his prior patent application serial number 11/250,235, filed Oct. 14, 2005, published as US-2006/0049215, by wetting the sorbent material with a polar solvent such as water or alcohol to promote desorption of more gas from the sorbent material. Normally, wetting the sorbent material with a polar fluid causes the sorbed gas to be desorbed more rapidly than desired, initially over-pressurizing the container and not leaving any reserve gas for release into the container as product is depleted and the pressure in the container drops. In its earlier application applicant sought to overcome that problem by wetting the sorbent with a limited amount of polar fluid in a reduced concentration, but this was only partially successful.

Accordingly, there is need for a pressurized dispenser holding a product and a propellant gas under pressure in a container, with a reserve supply of gas adsorbed on a gas-adsorbing material in the container for release of the reserve gas into the container in response to pressure drops, and with means to obtain desorption of the adsorbed gas from the gas-adsorbing material in a controlled manner and so that substantially all of the sorbed gas, approximately 80% or more, is eventually desorbed.

DISCLOSURE OF THE INVENTION

The present invention is a pressurized dispenser holding a product and a propellant gas under pressure in a container, with a reserve supply of gas adsorbed on a gas-adsorbing material in the container for release of the reserve gas into the container in response to pressure drops, and with means to obtain desorption of substantially all of the gas in a controlled manner.

The use of an ionized solid as a sorbent to attract and store CO₂ in a closed container enables the storage of CO₂ beyond the capacity that the container would have in the absence of the sorbent. In a 10 ounce container with one (1) ounce of the solid sorbent, the quantity of gas at 80 psig is 285% greater, by weight, than without the sorbent, and the quantity of gas at 100 psig is 251% greater than without the sorbent. Applicant has discovered that by wetting the sorbent with a non-polar fluid, release of the sorbed gas from the sorbent does not occur all at once but is achieved in a controlled manner, i.e. the sorbed gas is released in response to decrease in pressure, whereby a desired equilibrium pressure is maintained in the container until all or substantially all of the product has been dispensed.

The preferred sorbent is zeolite (sodium aluminum silicate) or activated carbon, although the sorbent may comprise any of: activated carbon, natural or synthetic zeolite, alumina, or a carbon fiber composite molecular sieve.

Preferred non-polar solvents have a low vapor pressure and include, for example, mineral spirits, isoparaffin, and EXXSOL D-95 by ExxonMobil. Other non-polar solvents can be used, depending upon the requirements and characteristics desired or needed in a particular application. In some applications very small amounts of a polar solvent, e.g. water, alcohol or acetone, may be used, alone or in combination with a non-polar solvent. Polar solvents alone, unless used in very small amounts as described hereinafter, generally are not satisfactory since they tend to cause release all at once of all or substantially all the adsorbed gaseous propellant. Although a polar solvent is effective to promote desorption of substantially all the sorbed gas, it does not achieve controlled release over the useful life of the container.

In preparing the sorbent in accordance with one aspect of the present invention, a gas adsorbing material is placed in a container or drum flooded with a propellant gas to be adsorbed. The container is at substantially atmospheric pressure and temperature, and in a preferred embodiment the gas adsorbing material, or sorbent, is zeolite and the gas to be adsorbed is carbon dioxide. It should be understood that other sorbents, such as activated carbon, for example, and other compressed gases, such as nitrous oxide, for example, could be used. The shipping and storage container is flooded with the propellant gas that is to be adsorbed on the sorbent so that the sorbent is exposed to an ambient atmosphere comprising that gas, so that during storage and handling prior to use the sorbent is not contaminated and the sorbed gas is not desorbed. This enables the sorbent to be stored and shipped in bulk quantities to a point of use. If desired, the gas adsorbing material can be wetted with a non-polar fluid prior to placing it in the storage container, or it can be wetted at a later stage in the filling process, as described hereinafter.

At the point of use a desired quantity of the sorbent is placed in a dispensing container to be pressurized with the propellant gas and filled with product. The sorbent can be pre-wetted with the non-polar fluid before it is placed in the dispensing container, or wetted after it is placed in the dispensing container by injecting an appropriate amount of the non-polar fluid into the container and into contact with the sorbent. The dispensing container is closed and sealed and additional propellant gas is pumped into the dispensing container so that a desired pressure is achieved when product is added. The propellant gas can be pumped into the dispensing container through a plug in the bottom of the container, or under the cup (under cup gassing) prior to crimping the container closed.

As product is dispensed and the pressure falls in the dispensing container some of the sorbed gas is released from the sorbent into the container to maintain the pressure at a desired level. Using a sorbent wetted with a non-polar fluid ensures that substantially all or at least most of the sorbed propellant gas will be desorbed as needed during use of the container, and the gas will be desorbed gradually as needed to restore equilibrium pressure in the container. The non-polar fluid is added to the zeolite in a ratio of from about 10% to about 90%, by weight, of non-polar fluid to zeolite, and optimally in the ratio of about 20% non-polar fluid to zeolite.

In accordance with another aspect of the invention the sorbent is saturated or loaded with propellant gas at ambient pressure and wetted with a non-polar fluid and then sealed in a packet that prevents contamination of the sorbent and desorption of the propellant gas from the sorbent. In a preferred embodiment the packet is a foil pack comprising a lamination of a heavy foil and polyethylene film. The foil packet is impermeable to the propellant gas and to moisture vapor and to the product to be dispensed. The sealed packets can be shipped and stored without loss of propellant gas from the sorbent. At the point of use one or more of the packets are placed in a dispensing container to be pressurized with the propellant gas and filled with product to be dispensed. Immediately prior to the packets being inserted into the container, or while they are being inserted, they are perforated in order to enable the sorbent to adsorb the selected compressed propellant gas and also so that during use the sorbed gas can be released into the container to maintain a desired pressure. Perforation of the packets can be accomplished with lasers or pins or slitters or other means known in the art. After the perforated packets have been inserted into the container, a propellant gas is charged into the container to a desired pressure and under cup sealed, followed by injecting a desired quantity of product into the container. If the container is of the barrier pack type wherein the product is kept isolated from the propellant by, e.g., a piston located between the propellant and the product, or wherein the product is placed in a bag, the product can comprise or can include either a polar fluid or a non-polar fluid. If the product and propellant are in fluid contact with one another in the container then the product must comprise only a non-polar fluid. During use of the container, as product is depleted and pressure in the container falls, additional propellant gas is released from the sorbent and passes through the perforations in the foil to restore pressure in the container. Use of the sealed foil packets simplifies the storage and handling of the sorbent in that it is not necessary to store the sorbent in a sealed bulk container having a propellant gas atmosphere. Smaller filling companies may find the packets more advantageous to use than the bulk containers described above.

In an alternate embodiment the sorbent packet can comprise sorbent pre-wetted with a non-polar fluid and sealed in a gas permeable membrane that passes only the propellant gas. In this embodiment the packet can be placed directly in the product whether the product comprises a polar fluid or a non-polar fluid. However, unless the packet according to this form of the invention is placed in the dispensing container immediately after the sorbent is wetted with the non-polar fluid, it would need to be stored prior to use in an environment comprising the propellant gas.

The non-polar solvent causes the sorbed gas to be released in a controlled manner in response to pressure drops in the container and most, if not all, of the sorbed gas will be desorbed during the useful life of the container. In particular, applicant has found that upwards of 85% of the gas will be desorbed. A ratio of solvent to zeolite in the range of from about 10% to about 90%, by weight, has been found by applicant to achieve the desired results, but optimum results are obtained at a ratio of about 20% and this is the preferred ratio. The quantity of sorbent material and the initial quantity and pressure of the propellant gas placed in the container are selected so that a desired pressure is maintained throughout the useful life of the container.

To load the sorbent with compressed propellant gas in accordance with an embodiment of the invention, the sorbent is placed in a can (dispensing container) and propellant gas is introduced under pressure into the can. Applicant has found that the sorbent becomes fully loaded or saturated, or at least nearly fully saturated, at a pressure of about 50 psi. Further adsorption can be achieved by increasing the pressure, but the sorbent is substantially fully saturated at a pressure of about 50 psi. The sorbent loaded with propellant gas can then be wetted with a non-polar fluid and sealed in a container or sealed in a foil packet or gas permeable membrane, as described above.

Addition of a polar solvent in the ratio of from about 0.1% to about 0.5%, by weight, of solvent to zeolite can be satisfactory under some circumstances.

The invention is particularly suitable in containers having a piston or bag that separates the product from the propellant, commonly referred to as barrier packs.

BRIEF DESCRIPTION OF THE DRAWINGS:

The foregoing, as well as other objects and advantages of the invention, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like reference characters designate like parts throughout the several views, and wherein:

FIG. 1 is a longitudinal sectional view of a first form of pressurized container incorporating the invention, wherein the container is a barrier pack of the bag-on-valve type.

FIG. 2 is a longitudinal sectional view of another form of pressurized container incorporating the invention, wherein the container is a barrier pack of the piston type.

FIG. 3 is a longitudinal sectional view of a further form of pressurized container incorporating the invention, wherein the product, propellant, and sorbent material are in the container together.

FIG. 4 is a perspective view of a foil pack containing a sorbent saturated with a propellant gas and wetted with a non-polar fluid in accordance with the invention.

FIG. 5 is an enlarged fragmentary sectional view of a foil and polyethylene laminate used in making the foil pack of the invention.

FIG. 6 is a longitudinal sectional view of a further form of the invention wherein solidified CO₂, or dry ice, is used to introduce the propellant gas into the container.

FIG. 7 is a perspective view of a sorbent packet wherein the sorbent is sealed in a gas-permeable membrane.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:

A first form of pressurized container incorporating the invention is indicated generally at 10 in FIG. 1. The container shown in this figure is a so-called barrier pack, more specifically commonly referred to as a bag-on-valve (BOV) container, and comprises a container 11, typically made of either metal or plastic, having a dome or end closure 12 carrying a valve assembly 13 with a bag 14 attached to the valve assembly. A gaseous propellant 15 is charged into the container outside the bag to pressurize the container, and product 16 is injected into the bag. When the valve 13 is opened product will be discharged through the valve. The structure described thus far is conventional.

In accordance with one aspect of the invention, a predetermined quantity of gas-adsorbing material 17, such as, e.g. zeolite or activated carbon, is placed in the container prior to assembly of the bag to the container. The valve and bag assembly are then attached to the container, and gaseous propellant is charged into the container outside the bag to pressurize the container and load the sorbent 17 with a reserve supply of the propellant gas. A non-polar solvent, e.g. mineral spirits, isoparaffin, or EXXSOL D-95 by ExxonMobil, is then injected into the container, preferably through the valve plug 19 in the container bottom, in an amount sufficient to wet the sorbent material 17 with the solvent. The amount of solvent injected into the container preferably is in the range of from about 10% to about 90%, by weight, of solvent to sorbent, and preferably in the ratio of from about 40% to about 50%, and most preferably in the ratio of about 20%. Product may be injected into the bag either before or after the solvent is injected into the container. As product is depleted from the container during use, the pressure drops and some of the propellant sorbed on the sorbent material is released into the container to restore equilibrium pressure. As more product is depleted, more propellant is released. Wetting of the sorbent with the non-polar solvent ensures that substantially all of the sorbed gas can be desorbed if needed during use of the container, but the gas will still be released incrementally in response to incremental drops in pressure.

The sorbent material may take any suitable and desired form or shape as illustrated and described, for example, in applicant's copending published patent application 2006/0049215, the disclosure of which is incorporated in full herein by reference.

Instead of the bag-on-valve container of FIG. 1, the invention can be used in a piston type barrier pack as shown at 20 in FIG. 2. In this form of the invention the sorbent material 17′ is placed in the container 11′ prior to insertion of the piston 18 into the container. It will be noted that in the example shown in FIG. 2 the sorbent 17′ is in the form of a shaped cohesive body rather than the loose granular material or pellets of FIG. 1. The piston is then inserted into the container and the top of the container closed and sealed. Gaseous propellant is then charged into the container below the piston to pressurize the container and load the sorbent 17′ with a reserve supply of the propellant. As in the previous embodiment; the sorbent is then wetted with a non-polar solvent injected through the plug 19 in the bottom of the container, either prior to or after product is injected into the container above the piston. Release of the sorbed gas to restore pressure as product is depleted is the same as in the previous embodiment.

A further form of the invention is indicated generally at 30 in FIG. 3. In this form, the propellant 15, product 16 and sorbent material are all in the same chamber in the container 11″, and the sorbent material is contained in a foil pack 31. As manufactured, the foil pack is impermeable to the propellant gas and to moisture vapor and product to be dispensed, and as seen best in FIG. 5 it comprises a laminate of heavy foil 32 and polyethylene film 33 enclosing a predetermined quantity of sorbent material (not shown, but which can be granular or powdered or shaped as a cohesive body) saturated or loaded with propellant gas and wetted with a non-polar fluid. Just prior to being inserted into the container or while being inserted the foil laminate is perforated with a plurality of small holes 34 or slits (not shown).

FIG. 4 shows the pack prior to being perforated, but with potential locations of holes shown in broken lines. The dispenser comprises a domed top 35 crimped to the top end of the container, a dispensing valve 13′ carried by the domed top, and a dip tube 36 extending from the valve to the bottom of the container. The foil pack containing the sorbent material saturated with propellant gas and wetted with a non-polar fluid as previously described is placed in the container prior to crimping the domed top in place. After the domed top is crimped in place, propellant gas is charged into the container to a desired pressure in accordance with conventional methods, or in accordance with the process described in applicant's copending application Ser. No. 11/805,995, the disclosure of which is incorporated in full herein by reference. Following pressurization of the container product is charged into the container in accordance with conventional methods or in accordance with the process described in applicant's copending application Ser. No. 11/805,995. Functioning of the wetted sorbent material to release stored gas is the same as in the previous embodiments.

FIG. 6 illustrates a fourth embodiment 40 in which propellant gas, CO₂, is placed in the container as a solid. In this form of the invention one or more pieces of dry ice 41 are dropped into the container 11″' prior to closing and sealing it, followed by the adsorbent material 17, e.g. zeolite wetted with a non-polar fluid. As the dry ice melts, gaseous CO₂ is given off, purging the container of air. The CO₂ continues to come off slowly as the dry ice melts, producing a low positive pressure in the container. The valve 13 is then crimped and sealed on the container, and product injected into the bag 14. Since not much CO₂ has been produced at this time there is very little back pressure, enhancing the filling procedure. The dry ice continues to melt, loading the zeolite and pressurizing the container. As product is depleted during use the pressure is restored as in the previous forms of the invention.

FIG. 7 illustrates a fifth embodiment 50 wherein the sorbent (not shown) is sealed in a gas-permeable membrane 51 that permits passage of the propellant gas but precludes passage of the product. The sorbent can be in the form of a powder, granules, pellets, or cohesive one-piece body, and can comprise any of the materials described above. An advantage of this form of the invention is that it can be placed directly in the product whether the product is a polar fluid or a non-polar fluid, and can be loaded with propellant gas either before or after being placed in the container.

Although particular embodiments of the invention are illustrated and described in detail herein, it is to be understood that various changes and modifications may be made to the invention without departing from the spirit and intent of the invention as defined by the scope of the appended claims. 

1. A gas storage and delivery system for restoring pressure as it is depleted from a pressurized container, comprising: a container holding a product under pressure to be dispensed from the container, said container having a normally closed discharge valve through which said product is dispensed when the valve is opened; a quantity of propellant comprising a gaseous material under pressure in the container, occupying a space in the container and applying to the product a predetermined pressure of from about 30 to about 180 psig to discharge product from the container when the valve is opened; a quantity of gas-adsorbing material in the container; a reserve supply of gaseous material adsorbed on the gas-adsorbing material, said reserve supply of gaseous material being desorbed from the gas-adsorbing material and released into the container in response to a decrease in pressure in the container, thereby restoring and maintaining a predetermined pressure in the container as product is depleted from the container; and wherein said gas-adsorbing material is wetted with a non-polar release-promoting agent to promote release of the sorbed gas in response to decreases in pressure in the container, and wherein release of substantially all of the sorbed gas is obtained if needed in response to decrease in pressure in the container.
 2. A gas storage and delivery system as claimed in claim 1, wherein: the gas adsorbing material is selected from the group consisting of activated carbon, natural or synthetic zeolite, alumina, and a carbon fiber composite molecular sieve.
 3. A gas storage and delivery system as claimed in claim 1, wherein: the gaseous material is selected from the group consisting of carbon dioxide and nitrous oxide.
 4. A gas storage and delivery system as claimed in claim 1, wherein: the gas adsorbing material is in the form of a one-piece cohesive body of material that retains its shape in the container and prevents dispersal of the material throughout the product.
 5. A gas storage and delivery system as claimed in claim 1, wherein: the gas adsorbing material is a granular or powdered material.
 6. A gas storage and delivery system as claimed in claim 5, wherein: a film or membrane cover is placed around the gas adsorbing material to prevent dispersal of it into the product but to enable flow of the stored gaseous material from the gas adsorbing material into the product.
 7. A gas storage and delivery system as claimed in claim 6, wherein: the film or cover prevents contact between the gas adsorbing material and the product.
 8. A gas storage and delivery system as claimed in claim 1, wherein: the non-polar fluid comprises mineral spirits; and the non-polar fluid is added to the container in the ratio of from about 10% to about 90%, by weight, of non-polar fluid to adsorbent material.
 9. A gas storage and delivery system as claimed in claim 1, wherein: the non-polar fluid comprises isoparaffin; and the non-polar fluid is added to the container in the ratio of from about 10% to about 90%, by weight, of non-polar fluid to adsorbent material.
 10. A gas storage and delivery system as claimed in claim 1, wherein: the sorbent material is contained within an envelope made of a material that is impermeable to the propellant gas and to moisture vapor and to the product to be dispensed, said envelope being perforated to enable passage therethrough of the sorbed gas and product but precluding passage therethrough of the sorbent.
 11. A gas storage and delivery system as claimed in claim 10, wherein: the envelope material comprises a heavy foil laminated with a polyethylene film.
 12. A gas storage and delivery system as claimed in claim 1, wherein: the sorbent is sealed in a gas-permeable membrane that permits passage of the gaseous material but precludes passage of the product.
 13. A gas storage and delivery system as claimed in claim 1, wherein: the propellant comprises carbon dioxide and is placed in the container in the form of dry ice that melts to form the gaseous propellant and pressurize the container.
 14. A gas storage and delivery system as claimed in claim 1, wherein: the sorbent is loaded with propellant gas and pre-wetted with the non-polar fluid prior to being placed in the container.
 15. A process of filling and pressurizing a dispensing container for dispensing a product pressurized by a propellant gas in the container, comprising the steps of: placing a desired quantity of gas-adsorbing material in the container; wetting the sorbent with a non-polar fluid; closing and sealing the container; pumping a predetermined quantity of propellant gas into the container; and injecting product into the container.
 16. A process of preparing a dispensing container for dispensing product under pressure from a pressurized gaseous propellant, comprising the steps of: placing a gas-adsorbing material in a storage container or drum flooded with a propellant gas at substantially atmospheric pressure and temperature so that the sorbent material can be stored and shipped in bulk quantities to a point of use without becoming contaminated and gas adsorbed on the sorbent is not desorbed; at a filling location placing a desired quantity of the sorbent in a dispensing container to be pressurized with the propellant gas and filled with product; closing and sealing the dispensing container and pumping additional propellant gas into the dispensing container so that a desired pressure is achieved when product is added later; and adding product to the container and shipping the filled and pressurized container to a point of sale or use.
 17. A process as claimed in claim 16, wherein: the sorbent is pre-wetted with a non-polar fluid before it is placed in the dispensing container.
 18. A process as claimed in claim 16, wherein: the sorbent is wetted with a non-polar fluid after the sorbent is placed in the dispensing container by injecting an appropriate amount of the non-polar fluid into the container and into contact with the sorbent.
 19. A process as claimed in claim 16, wherein: the sorbent is wetted with a non-polar fluid prior to placing it in the storage container. 